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Laser ultrasonic improvement and its application in defect detection based on the composite coating method.
Applied Optics
|October 18, 2022
Summary
This study optimized gold (Au) layer thickness on polydimethylsiloxane (PDMS) for enhanced photoacoustic conversion. The resulting Au/PDMS composite significantly improved laser ultrasonic signals for metal defect detection.
Area of Science:
- Materials Science
- Nanotechnology
- Acoustics
Background:
- Photoacoustic (PA) conversion efficiency is crucial for various sensing applications.
- Gold (Au) nanoparticles integrated with polymers like polydimethylsiloxane (PDMS) show promise for enhanced optical-to-acoustic transduction.
- Optimizing material properties is key to maximizing performance in PA and laser ultrasonic (LU) applications.
Purpose of the Study:
- To investigate and optimize the photoacoustic (PA) conversion efficiency of gold (Au)/polydimethylsiloxane (PDMS) composites.
- To determine the optimal thickness of the gold layer for maximizing PA signal generation.
- To evaluate the effectiveness of Au/PDMS coatings in enhancing thermoelastic laser ultrasonic (LU) signals for nondestructive metal inspection.
Main Methods:
- Modeling the PA process using the Drude-Lorentz model.
- Employing finite element analysis (FEA) for PA process simulation and optimization.
- Fabricating Au/PDMS composites with varying gold layer thicknesses.
- Coating aluminum alloys with optimized Au/PDMS composites for laser ultrasonic testing.
Main Results:
- The optimal gold layer thickness for the Au/PDMS composite was determined to be 35 nm.
- Coating aluminum alloys with the optimized Au/PDMS composite resulted in a nearly 100-fold improvement in thermoelastic laser ultrasonic (LU) signals.
- Defect mapping using thermoelastic LU signals with Au/PDMS coating showed high correlation (Pearson coefficient > 0.95) with ablation LU signals without coating.
Conclusions:
- The study successfully optimized Au/PDMS composite for enhanced photoacoustic and laser ultrasonic signal generation.
- The developed Au/PDMS coating significantly boosts the sensitivity of laser ultrasonic methods for metal defect detection.
- This research provides valuable insights for the nondestructive detection of defects in metals using laser ultrasound technology.
